package com.xinglong.spider.util;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

/**
 * @Author：胡云峰
 * @Date：2022/12/6 14:01
 */
public class RsaUtils {

    // Rsa 私钥（测试）
    public static String privateKey = "";

    // Rsa 公钥（采购平台）
    public static String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDHw5VJcgSnhcaENEin71tG jvXmTUr7GJWWd2W1FulnQSsOvQgnQVN2mhJu8z9nbRCNBf6mTkM4RUxNk3Sw XxfLZCtDjnTIVazXuTrK3JytCu02shn/guIDd5M19aiivGuHK8+IWG4TfitH rMOoAQY2lZ5BCHUgQvs8b0NNXDFSAwIDAQAB";

    /**
     * 私钥解密
     * @param text 待解密的文本
     * @return 解密后的文本
     * @throws Exception
     */
    public static String decryptByPrivateKey(String text) throws Exception
    {
        return decryptByPrivateKey(privateKey, text);
    }

    /**
     * 私钥解密
     *
     * @param privateKeyString 私钥
     * @param text 待解密的文本
     * @return 解密后的文本
     */
    public static String decryptByPrivateKey(String privateKeyString, String text) throws Exception
    {
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec5 = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKeyString));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec5);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] result = cipher.doFinal(Base64.decodeBase64(text));
        return new String(result);
    }

    /**
     * 公钥加密
     *
     * @param text 待加密的文本
     * @return 加密后的文本
     */
    public static String encryptByPublicKey(String text) throws Exception
    {
        return encryptByPublicKey(publicKey, text);
    }

    /**
     * 公钥加密
     *
     * @param publicKeyString 公钥
     * @param text 待加密的文本
     * @return 加密后的文本
     */
    public static String encryptByPublicKey(String publicKeyString, String text) throws Exception
    {
        X509EncodedKeySpec x509EncodedKeySpec2 = new X509EncodedKeySpec(Base64.decodeBase64(publicKeyString));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec2);
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] result = cipher.doFinal(text.getBytes());
        return Base64.encodeBase64String(result);
    }

    /**
     * 构建RSA密钥对
     *
     * @return 生成后的公私钥信息
     */
    public static RsaKeyPair generateKeyPair() throws NoSuchAlgorithmException
    {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(1024);
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
        String publicKeyString = Base64.encodeBase64String(rsaPublicKey.getEncoded());
        String privateKeyString = Base64.encodeBase64String(rsaPrivateKey.getEncoded());
        return new RsaKeyPair(publicKeyString, privateKeyString);
    }

    /**
     * RSA密钥对对象
     */
    public static class RsaKeyPair
    {
        private final String publicKey;
        private final String privateKey;

        public RsaKeyPair(String publicKey, String privateKey)
        {
            this.publicKey = publicKey;
            this.privateKey = privateKey;
        }

        public String getPublicKey()
        {
            return publicKey;
        }

        public String getPrivateKey()
        {
            return privateKey;
        }

        @Override
        public String toString() {
            return "RsaKeyPair{" +
                    "publicKey='" + publicKey + '\'' +
                    ", privateKey='" + privateKey + '\'' +
                    '}';
        }
    }

}
